My suggestion would be to mount the tires first then paint. I don't know of any fresh paint that will stand up to a tire machine or tire mounting tools.
Here's the trick I use. Mount the tires but don't air them up, this will leave a gap between the rim and the tire. I then take some cardboard and press it down on the rim edge to give me the pattern to cut the cardboard, which I cut just a little larger that the pattern. I do this with two pieces to slip into the gap between the tire and rim. Apply a little tape to keep it in place and the tire is masked off for painting.
When the paint is cured air up the tire and wala, done, and no chips in the paint from mounting the tire.
I usually have to go to some appliance store to find big cardboard like what covered a frig or dryer.
Dan
